Researchers In Brazil End Chloroquine Study After Participants’ Hearts Experience Life-Threatening Side Effects

Researchers are halting a Brazilian case study on chloroquine, and its effects on the coronavirus after participants began experiencing potentially heart-threatening complications.

The New York Times reports that researchers have put an end to a study of chloroquine, a drug that is heavily associated with fighting malaria, after volunteers in the study started having heart complications that could possibly result in death. Eighty-one hospitalized patients were involved in the Amazonian-funded case study and were used to test how effective the drug would be on attacking coronavirus, medRix reports.

However, researchers ceased the study early after “potential safety hazards” appeared as a result of the patients taking the drug. Each patient took a 50-milligram dose of chloroquine twice a day for five days, according to the report. Other volunteers were given one, 600-milligram dose every day for 10 days. “Preliminary findings suggest that the higher [chloroquine] dosage (10-day regimen) should not be recommended for COVID-19 treatment because of its potential safety hazards. Such results forced us to prematurely halt patient recruitment to this arm,” wrote researchers.

Patients who were taking the higher doses started experiencing arrhythmia, or irregular heartbeats within three days of taking the drug. Eleven patients died after six days, but no reports show whether it was due to the drug or the virus itself. The New York Post reports that the scientists said: “the trend towards higher fatality associated with the higher dose by day 6 of follow-up resulted in a premature halting” of giving higher doses to patients. Researchers say they concluded that the higher dosage is where they saw abnormal effects.

“To me, this study conveys one useful piece of information, which is that chloroquine causes a dose-dependent increase in an abnormality in the ECG (electrocardiography) that could predispose people to sudden cardiac death,” said Dr. David Juurlink, the head of the division of clinical pharmacology at the University of Toronto, Canada to the New York Times.